Shane Cameron's bid to join "Torpedo" Billy Murphy in the pantheon of New Zealand-born world boxing champions crumbled in Melbourne as Danny Green secured his place in Australian boxing history with an unprecedented fourth world title.

Green regained the vacant IBO world cruiserweight title he surrendered to American drug cheat Antonio Tarver in July last year by claiming a unanimous decision at the conclusion of 12 frustrating rounds for the Kiwi, who fought gamely after his left eyebrow was opened up by a head clash in the second round.

Neither fighter could land the telling blow but Green finished stronger and was comfortably ahead on the three judges' scorecards leaving Murphy's featherweight title in 1890 as New Zealand boxing's solitary success on the world stage.

Australian Graham Ingraham scored the bout 119-109 to Green; Steve Scott (New Zealand) found in the home-town favourite's favour 116-113 and American Glen Hamada agreed calling it 116-112.

Cameron dropped a division from his favoured heavyweight class to contest a world title for the first time and will now spend today's flight home to Auckland calculating the next phase of his career after suffering his third defeat in 32 fights, and first since David Tua won their all-Kiwi heavyweight showdown in Hamilton three years ago.

The 35-year-old's demolition job on Tua's nemesis Monte Barrett in July suggested Cameron was back on track, but the evergreen West Australian delivered a reality check as the Mountain Warrior failed to conquer his personal Everest before a capacity crowd at Hisense Arena.

Green is also contemplating his future after a morale-boosting victory that might convince the 39-year-old to battle on, amid rumours he was considering retirement after being stopped inside the distance during his most recent defeats to Krzysztof Wlodarczyk and Tarver last year.

The 39-year-old crowd and bookies' favourite now has a record of 33 wins (28 KO) and five losses.

Green entered the auditorium as a highlights package of his greatest hits played on the big screens - it resembled a retirement tribute and was hoisted skywards by his support crew after the final bell.

Cameron used his greater bulk from the opening rounds to lean on Green in a bid to sap his energy and negate the Australian's much-vaunted foot speed.

Despite being cut, Cameron stayed aggressive in the third, after cut man Ken Reinsfield staunched the bleeding, and caught Green with a sharp left hand.

Green also indulged in wrestling tactics from the fifth round onwards as the veteran's stamina was tested, initially a questionable ploy as Cameron dominated the close quarters exchanges with crisp uppercuts and a firm right hand.

Green landed an early left-right combination as Cameron backed on to the ropes to set the early pace in the sixth, but again the New Zealander responded with a left jab that rocked the Australian's head back for the first time.

Cameron dislodged Green's mouthguard inside the opening minute of the seventh round, when another left jab hit the target but once it was retrieved and reinserted the favourite rallied.

Green upped his work rate in the eighth as Cameron started to tire noticeably for the first time and although he lost his mouthguard for a second time in the ninth, again the blow did not hurt the Australian.

Both fighters were taking the strain from the 10th round onwards as the contest turned ugly but Green was finishing stronger.

He fired up the partisan crowd with a sequence of admittedly innocuous rights to Cameron's head while they clinched, and then wrestled Cameron to the ground to wild applause, but no sanction from referee Pat Russell.

The American also ignored Green's tendency to strike Cameron after the break - not that the blows caused any obvious damage, just irritation.

A delighted Green, meanwhile, gave his fans what they wanted...almost.

Asked if he was going to retire a winner, Green would only commit to this: "I'm getting on the cans with the boys."